I have a LS 427, 540/540. The original pump was replaced by a 255 but that has packed it in. I've been out of touch for quite some time and wanted to know what is a good replacement. Just want to replace back into the stock can.

 

A Ti automotive (used to be Walbro) 450 pump will fit where the 255 pump fit and be more than enough pump for you. It’s good to 800+ hp.

 

Thanks.

 

IMO 450 is overkill and might even override your fuel pressure regulator unless you have a adjustable mechanical FPR. When sizing a pump, you should consider how much fuel the pump is pumping every minute as you drive. If you do a lot of city driving, the 450 will recycle the entire tank in minutes at 450 liters per hour. Even at highway cruise, fuel consumption will never exceed the output of a 450 lph pump. You might consider a 340 LPH pump instead.

You also have to consider the amp draw of a 450 lph pump compared the stock 255 lph pump. If you still have stock wiring you might overload the circuit and blow fuses.

A 255 lph and a 340 lph draw a maximum of 12-14 amps. That's why companies like Racetronix suggest an upgraded wire harness with a dedicated relay and fuses to handle the additional amp requirements of larger than stock fuel pumps. You also might have to upgrade the connector at the top of the fuel pump hat dependent upon your fuel pump assembly and whether it has been upgraded or not. Some bulkhead connectors can handle up to 30 amps for big pump or dual pumps.

Go to Racetronix website or review threads in this forum for calculating the fuel requirements for maximum RWHP or crank HP for your application.

For example: a Racetronix 255 LPH pump with an upgraded wire harness to the single 255 lph pump was adequate for my 1998 Procharged Z28 that put out 545 RWHP (HP to the wheel - not at the crank) at less than 80 percent duty cycle with 60 PSI injectors at 8 lbs of boost. Boosted engines require more fuel than NA engines..